Access point which sends geographical positioning information from the access point to mobile terminals and mobile terminal which receives the information and estimates the position thereof based on said information

ABSTRACT

The invention relates to an access point ( 20 ) which sends geographical positioning information from the access point to mobile terminals ( 10 ) and to a mobile terminal which receives this information and estimates the position thereof based on said information. Geographical-locating architecture for WiFi 802.11 mobile terminals on ADSL access points generally consists of including geographical positioning information, i.e., the geographical coordinates of the access point during the registration phase thereof. The access point includes this geographical information in the information posted so that the mobile terminals can be connected to same. The mobile terminals can thus know the geographical location where they are located with an approximation that will depend directly on the number of access points that the mobile terminal can detect.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention is applied to the field of the information andtelecommunications technologies, more specifically, to end user-orientedwireless personal communications technologies through a non-cellularwireless communication protocol, such as 802.11 (in any of its standardversions), on PC, PDA or mobile telephony platforms, etc.

2. Description of the Related Art

Services in which geographical information is particularly relevant arewidespread today. They are value-added services in the field of personalnavigation, in emergency services with positional information, near-byservice search services, tourism information, etc.

Services of this type are spreading as a result of the popularity of GPSnavigation devices which are progressively being integrated in high-endmobile terminals. However, they are inaccessible for the mobile devices,PDAs or portable computers in which there is no GPS receiver, or inwhich there is a GPS receiver on board or connected via Bluetooth, butit does not have a clean LOS (Line Of Sight) connection with a set ofpositioning satellites, such as in indoor settings for example.

Knowing the geographical positioning information of a wireless device isfundamental for:

-   -   being included in transactions started from the user of the        mobile terminal against Internet servers in which knowing the        approximate geographical position is relevant (map servers,        etc.)    -   the user of the mobile terminal to be able to know his        approximate geographical position for obtaining services        contextualized to his geographical position, such as for        example, georeferencing photographs taken with his terminal and        subsequently uploading them to a network server for storage.    -   the mobile terminal to be able to launch emergency services        accompanied by an approximate estimation of the location of the        terminal.    -   the user of the terminal to be able to enjoy geographical        information- dependent services provided by the mobile telephony        operator, such as conditioned diversions, georeferenced        warnings, etc.    -   implementing local data exploitation services in the mobile        terminal by means of knowing the approximate position, such as,        navigators in the terminal for example.

Mobile terminal locating methods for cellular-type access networks,which are defined in industry standards, are known. However, there arestill few proposals for implementing mobile terminal locating mechanismsin non-cellular wireless communication networks.

Some examples of non-cellular wireless communication systems whichlocate mobile terminals are discussed below:

Patent application US 2008/0042901 describes a proposal which isfundamentally aimed at defining software processes for obtaining anestimation of the geographical position from power measurements taken ofthe signal in wireless-type, but not necessarily cellular, devices.

The proposal described in patent application WO 2007/082912 isfundamentally oriented at obtaining a list of available hotspots ingeographical positions, but not at locating the wireless terminalitself.

Therefore, one objective of the present invention is to provide newmechanisms for locating mobile terminals in wireless non-cellularnetworks, overcoming the limitations of known mechanisms.

DESCRIPTION OF THE INVENTION

To that end, according to one aspect of the invention, an access pointaccording to independent claim 1, a mobile terminal according toindependent claim 12 and methods according to independent claims 13 and15 are provided. Dependent claims include particular embodiments of theinvention.

According to one aspect of the invention, an access point for anon-cellular wireless communication system comprising means for sendingdata to one or more mobile terminals is provided. These means forsending data are configured for sending geographical positioninginformation from the access point to the mobile terminals. Therefore,the geographical positioning information will be publicly accessiblefrom the mobile terminals which receive the signal from the accesspoint.

According to another aspect of the invention, a mobile terminal for anon- cellular wireless communication system comprising means forreceiving data from at least one access point is provided. These meansfor receiving the data are configured for receiving geographicalpositioning information from the access point. The mobile terminalcomprises means for estimating the position of the mobile terminal basedon the geographical positioning information received from the accesspoint.

The geographical positioning information will be obtained by thenon-cellular mobile terminal:

-   -   in both indoor and outdoor settings,    -   without needing an on-board GPS/A-GPS receiver,    -   without needing to start data connections to external servers.

According to one embodiment of the invention, the means for sending thedata from the access point are configured for sending the geographicalpositioning information by means of broadcast in beacons, preferably ina Service Set Identifier (SSID) defined in the WiFi or WiMax standard,or other wireless non- cellular technologies having a similar behavior.Therefore, an inference mode for inferring the geographical position ofthe mobile terminal only by means of receiving the broadcast informationfrom the access points, together with the network identifier (given bythe SSID), enabling the connection of the WiFi mobile terminals to aspecific access point is implemented. Each WiFi mobile terminal canreceive the signal from several near-by access points. In residential orcommercial areas, the deployment density of WiFi access points meansthat on average, a WiFi terminal will detect an increasing mean numberof access points which, in large cities and always depending on the typeof area, will be above 3 detected accesses, making this invention viablein urban settings.

According to another embodiment, the access point comprises means forobtaining the geographical positioning information of an entity locatedin a telephone network, for example of a digital subscriber line accessmultiplexer (DSLAM). Said information is preferably obtained by theaccess point during a registration or access permission checking step.This registration process between the access point and the DSLAM isperformed on the PPP PAP protocol (Point-to- Point Protocol PasswordAuthentication Protocol) or PPP CHAP protocol (Point-to- Point ProtocolChallenge Handshake Authentication Protocol), on the messages of whichboth the user credentials and the acceptance or refusal of the accesspermissions are transported to the access point.

In the registration process, the DSLAM access a database with userinformation and user passwords for accepting the request to access theaccess point or to refuse such request. The database will store the userinformation, including the access point telephone number. This numberwill be directly associated with a user subscription and to a specificpostal address (city, street, number). This postal address will bedirectly associable with specific geographical coordinates by means of asimple translation process. Therefore, the geographical coordinates ofthe access point can be sent back to same in the registration phase whenthe user credentials are accepted for obtaining access to the IP networkof the Internet Service Provider (ISP).

In the event that the access point does not have access to the userdatabase for various reasons, the access point administrator couldeventually provide the geographical coordinates to the access point bymeans of an administration interface.

According to an additional aspect of the invention, a method implementedin an access point for a non-cellular wireless communication system isprovided, characterized in that it comprises the step of the accesspoint sending geographical positioning information from the access pointto mobile terminals.

The method preferably comprises the step of the access point obtainingthe geographical positioning information of an entity located in atelephone network.

According to another aspect of the invention, a method implemented in amobile terminal for a non-cellular wireless communication system isprovided, characterized in that it comprises the step of receivinggeographical positioning information from at least one access point andestimating the position of the mobile terminal based on the geographicalpositioning information received from the access point.

The methods are preferably implemented by means of a computer program.

These and other aspects of the invention will be evident from andclarified in reference to the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will be more clearlyunderstood from the following description of an embodiment, provided asa non- limiting example, with reference to the attached drawings.

FIG. 1 shows the ADSL access architecture through an access point usingthe WiFi 802.11 protocol.

FIG. 2 shows a locating scenario by triangulation from three positionsignals from respective access points.

FIG. 3 shows the proposed signaling diagram.

In all the drawings, similar reference numbers refer to similarelements.

PREFERRED EMBODIMENTS OF THE INVENTION

The elements forming the infrastructure for ADSL access through anaccess point using the WiFi 802.11 protocol are depicted in FIG. 1. FIG.1 also shows the breakdown of the internal modules of the elements ofthe proposed architecture. These elements are functional, and thereforedepending on the particular implementation of the solution, they can beaggregated in physical network elements in a different manner.

FIG. 1 shows a mobile terminal 10 or wireless device, comprising a MODEM12 and a module 14 for estimating the position of the mobile terminal.The mobile terminal communicates with an access point 20 through aninterface 60 according to the WiFi 802.11 protocol. The access point isconnected by means of the subscriber twisted-pair cable to a telephonenetwork, more specifically to a digital subscriber line accessmultiplexer (DSLAM) 30. This architecture allows the mobile terminal toaccess the IP network 40 of the Internet Service Provider. To determineif the user has the right to access the network, the DSLAM validates thecredentials of the access point against the ADSL user database 50. Thisregistration process between the access point and the DSLAM is performedon the PPP PAP protocol (Point-to-Point Protocol Password AuthenticationProtocol) or PPP CHAP protocol (Point-to-Point Protocol ChallengeHandshake Authentication Protocol), 70 [1], [2], [3], on the messages ofwhich both the user credentials and the acceptance or refusal of theaccess permissions are transported to the access point.

In the registration process, the DSLAM access a database with userinformation and user passwords for accepting the request to access theaccess point or to refuse such request.

This database will store the user information, including thegeographical telephone number (+349XXXXXXXX) from which the access pointstarts the access process. This geographical number will be directlyassociated with a user subscription and with a specific postal address(city, street, number). This postal address will be directly associablewith specific geographical coordinates by means of a simple translationprocess.

Therefore, the geographical coordinates of the access point can be sentback to same in the registration phase when the user credentials forobtaining access to the IP network of the Internet Service Provider areaccepted.

In the event that the access point does not have access to the userdatabase for various reasons, the access point administrator couldeventually provide the geographical coordinates to the access point bymeans of an administration interface.

The access point WiFi publishes in beacons (see [4]), the informationcorresponding to the Service Set Identifier (SSID) which will identifythe access point and the type of services offered by same, the timestampof time of sending, for transmission delay measurements, and theapproximate geographical position coordinates of the access point, whichcan be included in the Parameter Sets field in the same SSID, or in anadditional ad-hoc field.

Therefore, the geographical position information will be publiclyaccessible from the wireless terminals (mobile terminals) which receivethe signal of the access point.

The mobile terminal can estimate its geographical position in severalways. In the event that it only receives a signal from a single accesspoint, it can only roughly estimate the position of the mobile terminal.The best estimation of the position will be the position of the accesspoint itself, similarly to the Cell of Origin (CoO) based locatingmethod in cellular telephony, as specified in [5]. It is possible toobtain an estimation of the reliability of the value of the position bymeans of power measurements taken of the signal received from the accesspoint, however this will be very dependent on the capabilities of theterminal itself.

In the event that the mobile terminal receives geographical coordinateinformation from several of the detected access points, the position ofthe device itself with can be estimated more precisely. To that end,there are several recently developed techniques which can, in principle,be used. A non-comprehensive list of some of the possibilities isprovided below.

-   -   Assigning the position of the mobile terminal (wireless) to the        position of the access point the signal of which is received        with a stronger power. This option has the advantage of        requiring low processing power and complexity in the wireless        terminal, but it obtains a less reliable position.    -   Performing triangulation from the signals which are received        with a similar power. To obtain a more reliable reading, it will        be necessary to have three or more received signals, as depicted        in FIG. 2. In the event that the power with which the signal of        the access points is not similar, one of the possible options is        to weight the distance between the mobile terminal and the        access point depending on the relative power at which the signal        is received, as depicted in FIG. 2 (r₁, r₂, r₃).

The signaling diagram of the solution is depicted in FIG. 3. Twodifferent phases can be seen therein. The first phase is theregistration phase 300 of the access point in which the latter obtainsthe geographical coordinate information that is going to be posted,stored in the user database 50. Secondly, the broadcast phase 310 inwhich the access point posts its geographical positioning informationand said information is collected by a mobile terminal, can be seen.

The initial registration phase 300 of the access point 20 begins afterthe same is switched on 320. During this initial registration process,the access point launches a PPP AuthenticateRequest 330 to the DSLAM 30in a traditional manner, including the authentication credentials forthe registration. The DSLAM checks 340 against the ADSL user database 50the identity and validity of the password included in the previousAuthenticateRequest and returns, if successful, an Authenticate-ACK 350,according to the standard method included in [3]. In the Message fieldof the Authenticate-ACK message, the DSLAM 30 includes the informationrelating to the geographical coordinates of the access point, extracteddirectly from the user and credentials database 50.

Once the access point 20 receives the geographical coordinateinformation, the registration phase 300 ends and the broadcast phase 310begins. The access point 20 has internally stored (step 360) thegeographical coordinates and sends them in the SSID 370 of the wirelessnetwork. Finally, the mobile terminal estimates its geographicalcoordinates from one or more received signals (step 380).

Now the functionality of some of the elements shown in FIG. 1 will bedescribed.

The geographical coordinates of the public telephone numbers(geographical numbers) having access subscription are stored in thedatabase 50.

The element referred to as DSLAM 30 manages the registration requestsfrom different access points and routes the IP traffic to thecorresponding public IP network 40. It connects with the access pointthrough the public basic telephony network (BTN).

In the interface between the access point 20, and more specifically theMODEM 24 of the latter and the element DSLAM 30, there is a PPPinterface 70 in which the corresponding messages are exchanged duringthe registration phase 300 of the access point. According to [3], thesemessages are AuthenticateRequest (MODEM->DSLAM) and Authenticate-ACK(DSLAM->MODEM) in the case of positive registration or Authenticate-NACK(DSLAM->MODEM) in the case of negative registration. As has beenexplained, the recommended implementation for communicating thegeographical position from the access point is for the DSLAM to send thecorresponding coordinates in the Authenticate-ACK message, specificallyin the multipurpose Message field, in which it is possible to transportcorresponding information to upper layers without affecting theauthentication protocol between the elements.

The element that will perform the tasks of modulation/demodulationtowards the public basic telephony network (BTN), the MODEM 24, isdefined in the element generically referred to as “Access point” 20. TheMODEM performs tasks of adapting communication physical layer protocolsto go, for example, from a radio link to a cable link. This element willreceive its positioning information, stored in the geographical positionDatabase (50) for each telephone number. Upon receiving thatinformation, the MODEM will include it in the radio signal which will beposted for all the users to enable connection to the access point.Therefore, in this embodiment the MODEM corresponds to the means forobtaining the geographical positioning information of an entity locatedin a telephone network defined in the claims.

The access point 20 further comprises the router 22, which performstasks of routing IP traffic over the different physical layer protocols.In this case it is of a physical protocol 802.11. In this embodiment therouter corresponds to the means for sending data to one or more mobileterminals defined in the claims.

However, it is possible to assign the functionality of obtaining thegeographical information from the access point and to send these data tothe mobile terminals to any of the two nodes, the MODEM 24 and therouter 22, or to the two nodes as a whole.

The wireless interface 60 between the access point and the mobileterminal 10, in the particular case of WiFi connections, is defined bythe IEEE 802.11 standard. This standard defines the broadcast messageswhich are used by the access point for posting its identity and otherdata, so that near-by wireless devices (mobile terminals) can connect tothe access point. These broadcasts are referred to as beacons. There areseveral fields in these messages which are posted by the access point,including the “Parameter sets” field, where multipurpose information isstored. A possible implementation is to include in this field thegeographical information sent by the DSLAM in the registration step. Inthe particular event that there is another type of wireless interfacebetween the elements, the preferred implementation is similar to thepreceding implementation for the case of IEEE 802.11.

A MODEM 12 performing tasks of modulation/demodulation between theinternal traffic of the mobile terminal and the traffic exchanged withthe access point is included in the mobile terminal 10. The tasks ofthis element are to adapt the 802.11 physical layer protocol. The MODEMcorresponds to the means for receiving data from at least one accesspoint defined in the claims.

The mobile terminal optionally comprises a module 14 performing thecorresponding mathematical calculations intended for suitably estimatingthe position of the mobile terminal, such as those related totriangulating signals or weighting such signals, depending on the powerreceived. The module corresponds to the means for estimating theposition of the mobile terminal defined in the claims.

Although the invention has been illustrated and described in detail inthe drawings and in the preceding description, such illustration anddescription must be considered as illustrative or exemplary and notrestrictive; the invention is not limited to the disclosed embodiments.

For example, though the preferred embodiment of the invention uses theIEEE 802.11 protocol, the invention can be extended to other types ofnon-cellular wireless access technologies, such as WiMAX or others to beidentified or defined in the future.

Other variations to the disclosed embodiments can be understood andcarried out by persons skilled in the art when putting the claimedinvention into practice, from studying the drawings, the description andthe attached claims. In the claims, the expression “comprising” does notexclude other elements or steps, and the indefinite article “a” or “an”does not exclude a plurality. A single processor or other unit canperform the functions of several elements mentioned in the claims. Themere fact that certain measurements are mentioned in the dependentclaims which are different from one another does not mean that acombination of these measurements cannot be used in a more advantageousmanner. A computer program can be stored/distributed in a suitablesupport, such as an optimal storage support or a solid state supportsupplied with or as part of other hardware, but it can also bedistributed in other manners, such as through the Internet and otherwired or wireless telecommunication systems. Any reference sign in theclaims must not be interpreted as being a limit to the scope.

Literature

-   [1] IETF RFC 1661 “The Point-to-Point Protocol (PPP)”-   [2] IETF RFC 1994 “PPP Challenge Handshake Authentication Protocol    (CHAP)”-   [3] IETF RFC 1334 “PPP Authentication Protocols”-   [4] IEEE 802.11, 1999 Edition (ISO/IEC 8802-11: 1999) IEEE Standards    for

Information Technology—Telecommunications and Information Exchangebetween Systems—Local and Metropolitan Area Network—SpecificRequirements—Part 11: Wireless LAN Medium Access Control (MAC) andPhysical Layer (PHY) Specifications

-   [5] 3GPP TS 23.171 “Location Services (LCS); Functional description;    Stage 2 (UMTS)”.

1. Access point for a non-cellular wireless communication systemcomprising means for sending data to one or more mobile terminals,characterized in that the means for sending the data are configured forsending geographical positioning information from the access point tothe mobile terminals.
 2. Access point according to claim 1,characterized in that the means for sending the data are configured forsending the geographical positioning information by means of broadcast.3. Access point according to claim 2, characterized in that the meansfor sending the data are configured for sending the geographicalpositioning information in beacons.
 4. Access point according to claim3, characterized in that the means for sending the data are configuredfor sending the geographical positioning information in the Service SetIdentifier.
 5. Access point according to claim 1, characterized in thatit comprises means for obtaining the geographical positioninginformation of an entity located in a telephone network.
 6. Access pointaccording to claim 5, characterized in that the entity located in thetelephone network is a digital subscriber line access multiplexer. 7.Access point according to claim 6, characterized in that the means forobtaining the geographical positioning information are configured forthe access point to obtain said information in a registration or accesspermission checking step.
 8. Access point according to claim 7,characterized in that the registration step is performed on a PPPprotocol.
 9. Access point according to claim 1, characterized in that itcomprises an administration interface so that an access pointadministrator provides the geographical positioning information to theaccess point.
 10. Access point according to claim 1, characterized inthat the means for sending the data work according to the WiFi or WiMaxprotocol.
 11. Communication system comprising an access point accordingto claim 5 and an entity located in a telephone network, characterizedin that the entity is configured for obtaining information relating tothe geographical positioning of the access point from a user databaseand sending it to the access point.
 12. Mobile terminal for anon-cellular wireless communication system comprising means forreceiving data from at least one access point, characterized in that themeans for receiving the data are configured for receiving geographicalpositioning information from the access point and in that the mobileterminal comprises means for estimating the position of the mobileterminal based on the geographical positioning information received fromthe access point.
 13. Method implemented in an access point for anon-cellular wireless communication system, characterized in that itcomprises an step of sending geographical positioning information fromthe access point to mobile terminals.
 14. Method according to claim 13,characterized in that it comprises an step of obtaining from the accesspoint the geographical positioning information of an entity located in atelephone network.
 15. Method implemented in a mobile terminal for anon-cellular wireless communication system, characterized in that itcomprises an step of receiving geographical positioning information fromat least one access point and estimating the position of the mobileterminal based on the geographical positioning information received fromthe access point.
 16. Computer program comprising code means suitablefor performing the steps of claim 1, when said program is run in acomputer.